This invention relates to gate mechanisms in general, and more particularly to an improved type of slide gate for regulating fluid flow.
Slide gates are not new in the art. Such gates are typically employed to regulate fluid flow through a passageway or channel and generally comprise a frame assembly which defines an opening, a gate member mounted to the frame assembly and adapted for movement therein so as to selectively open up or close off the opening in the frame assembly, some form of sealing means for assuring a watertight seal between the gate to close off the opening in the frame assembly, and operating means for urging the gate member to move within the frame assembly. The frame assembly of the slide gate is generally mounted to the walls defining the passageway or channel through which the fluid flows in such a way that substantially all of the fluid flow must pass through the opening in the frame assembly. In this way a slide gate is formed which allows one to regulate the fluid flow passing through the slide gate by controlling the position of the gate member within the frame assembly. Typical slide gates are described and illustrated in my U.S. Pat. No. 3,760,593 and the references cited therein. Other forms of gates are disclosed in my U.S. Pat. No. 4,028,896 and the references cited therein.
Unfortunately, there have been a number of problems associated with the sealing means used to ensure a watertight seal between the gate member and the frame assembly. The most common type of seal presently in use is the resilient bulb seal, generally known as the P-type or J-type seal. Slide gates with P and J-type seals are made, for example, by Coldwell Wilcox Co. of Fairfield, Connecticut and Rodney Hunt Co. of Orange, Massachusetts. This type of seal comprises a flat elongated body having an enlarged hollow or solid bulb at one end, and is designed to be positioned with its flat body mounted to the frame assembly and its enlarged bulb compressed between the movable gate member and a part of the frame assembly. The compressed bulb fills the region between the gate member and the adjacent part of the frame assembly so that a watertight seal is provided therebetween, while allowing movement of the gate member relative to the frame assembly. Alternately, the compressed bulb seal is sometimes positioned between the gate member and the wall defining the passageway or channel. In either case, in practice the compressed bulb design has exhibited a tendency to bind movement of the gate member within the frame through excessive friction therewith, so that as a result stronger operating means are required for opening and closing the gate member and the seal lifetime is decreased. In addition, the bulb portion of the seal exhibits a tendency to dam fluid (and any debris carried by the fluid) about the seal so as to impede fluid flow through the slide gate when the gate member is not closing off the opening in the frame. Bulb type seals also require separate seal retainers at the sides of the gate which are expensive, complicate installation and repair, and tend to make it difficult to predict the amount of drag on the gate.
Alternative seal designs which do not use a compressed bulb concept have exhibited similar or worse problems, such as failing to make a tight seal, having a short lifetime or having a high manufacturing or installation cost.
As a result the primary object of the present invention is to provide a slide gate which utilizes novel sealing means that substantially eliminate or reduce the aforementioned problems.